The present invention relates to fountains, particularly display fountains, although the invention in its different aspects may also have other applications.
Display fountains come in many shapes and sizes. Water “features” are a common and increasingly popular aspect of domestic garden scenery. Larger displays are frequently employed in public places and have long been an adjunct to architectural or sculptural works. Most fountains are static, in that they have a single mode of operation—they are either on, or off. Static fountains are the simplest and least expensive, and generally only require a pump or water supply to operate. These kinds are affordable by most people and are seen in many garden ponds. Various nozzles provide different effects from sprays to jets, and may be arranged to entrain air so that a foaming spray is generated.
However, more sophisticated fountains are dynamic in that their operation is controlled, and accordingly varied, by different jets being switched on or off, or having their pressures varied, or redirected. The control arrangement is invariably electronic with greater or lesser complication, and involves the use of selectively operable mechanical valves that can interrupt flow, as may be desired. By this means a wide variety of different effects can be achieved. But such variety comes at a significant cost, not just in terms of price, but also of reliability. Fountains generally involve recycling pond or fountain pool water, and debris eventually builds up and can block valves etc.
One recent development in fountain displays is the use of slugs of water. Although a continuous jet of water involves continuous motion, this fact disguised by a complete arc of a water jet, which can appear somewhat static. If, however, slugs of water are generated, which slugs have a beginning and an end, the motion is brought home to the viewer. U.S. Pat. No. 5,979,791 and U.S. Pat. No. 6,119,955 both disclose arrangements for producing slug jets, one involving the use of a syringe-type of arrangement, and the other involving a plug rapidly releasing and closing an orifice of a chamber containing liquid under pressure.
U.S. Pat. No. 5,918,809 discloses a water display arrangement in which a float is provided with nozzles supplied by flexible water pipes, the reaction from the nozzles moving the float about on a pond or pool surface and creating interesting effects. However, mechanical switching arrangements are provided.
Numerous patents disclose fluidic arrangements for producing oscillating jets, whose main application appears to be in the automotive field for vehicle windscreen and headlight washing. Examples are to be found in U.S. Pat. No. 6,253,782, U.S. Pat. No. 5,213,269, U.S. Pat. No. 5,181,660, EP-A-0208174 U.S. Pat. No. 4,398,664, U.S. Pat. No. 452,867 and WO-A-7900361.
EP-A-0331343 discloses the use of a fluidic bistable oscillator in the production of a spray of droplets having a narrow size spectrum. SU-A-478622 discloses a display fountain using a diverter to provide alternating jets under pneumatic control.